1. Field of Invention
The present invention relates to a kind of luminous display device, and more particularly, relates to an electroluminescent wire which utilizes electric field for light emitting purposes.
2. Description of Related Arts
Theoretically, an electroluminescent wire has the same luminous principle compared with the powder electroluminescent device, wherein the electroluminescent material is mainly the luminous material of II to VI groups. The luminous material will emit composite lights in the electric field. Furthermore, the luminous material consists of microcrystalline powder of 5 to 30 micron, in which a quantity of emitting line pairs existed so as to ensure the light emitting in the evenly distributed electric field.
U.S. Pat. Nos. 5,485,355, 5,869,930, 6,400,093, EP0693803A, JP7-235375, CN ZL01250547.1, and CN ZL01251151.X respectively described the structure of the electroluminescent devices, wherein the metal wire is exclusively used a base wire, durable moisture-proof green luminous material is used as light emitting material, ITO material is used as the transparent conductive layer, PVC plastic is used as sealing layer, and colorized organic fluorescer are used for coloring purposes. U.S. Pat. Nos. 4,585,673, 5,156,885, and ZL01138921.4 also disclosed complex wrapping techniques for luminous material in the electroluminescent wire.
More or less, the luminous wires disclosed by prior arts have the following drawbacks:                A) The electroluminescent wire cannot be used independently for light emitting purposes. For example, it must be mounted or embedded into a certain surface. That is to say, it needs a groove, clip, glue, or bracket for positioning purposes. This greatly limits its application in all perspectives.        B) The white light is realized by adding pink organic dye into electroluminescent powder. However, such method is not stable, and the final product is short-lived. What is worse, the color purity is not well. Whenever the electroluminescent wire was exposed outside for 10 days or continuously being performed over 100 hours, the organic dye would have been fade, thus resulting white light changed into green or light blue, and leading other colors changed.        C) Due to the fact that PVC or PE is used as sealing material, the moisture-proof and durability function would not be guaranteed. As a result, the moisture-proof green luminous material, having a longer life span have to be used thus causing the overall costs of the luminous wire unnecessarily increased and manufacturing procedure complicated.        D) Since the transparent conductive layer uses ITO making of In2O3 and its dopant, its cost would be rather expensive and susceptible under bad weather. Therefore, such luminous wires are always kept within a low temperature refrigerator for maintaining a relatively short three-month storage life span.        E) The weight and hardness of the base wire would limit the applications of such luminous wires.        
The present inventor has improved the durability, color stability, and structure of the electroluminescent wire for several times respectively in Chinese patents CN96118930.4, 98122739.2, 0018424.5, 01133342.1. However, the shortcomings of the traditional luminous wires still existed. For instances, the manufacturing process is still complex and the adhesion between the dielectric layer and the luminous layer is still weak. That is to say, the improved procedure is still not suitable for mass production. On the other hand, the life span of the improved luminous wires is not stable, and such product is still from independent usage.